1. Field of Invention
The present invention relates to a soft-switching inverter and, more particularly, to a low-power, high-efficiency, high-step-up-ratio inverter for providing electricity to an AC load or the grid.
2. Related Prior Art
To prevent the global weather and ecosystem from getting worse due to the use of fossil fuel, lots of efforts have been made on developing solar cells, fuel cells and wind turbines. It is difficult to build large power plants based on renewable energy in densely populated regions such as Taiwan. Instead, small decentralized power plants based on renewable energy are popular in the densely populated regions.
The small decentralized power plants may be classified into three categories. At first, there are stand-alone systems. A stand-alone system provides electricity based on decentralized renewable energy such as the sun light and wind. The stand-alone system provides electricity to a load and/or a battery. The stand-alone system recharges the battery when it provides more electricity than the load consumes. The battery provides electricity to the load when the stand-alone system provides less electricity than the load consumes.
Secondly, there are grid-connection systems. A grid-connection system provides electricity to a load and/or the grid. The grid-connection system provides electricity to the grid when it provides more electricity than the load consumes. The grid provides electricity to the load when the grid-connection system produces less electricity than the load consumes.
Thirdly, there are hybrid systems each as a combination of a stand-alone system with a grid-connection system. A hybrid system operates like a grid-connection system when the grid operates normally. The hybrid system operates like a stand-alone system when the grid fails.
There have been few stories of building conventional grid-connection systems on low-capacity photovoltaic modules. The present invention is intended to obviate or at least alleviate the problems encountered in prior art.